(a) Field of the Invention
The present invention relates to an iron-based amorphous alloy and a method of manufacturing the same. More particularly, the present invention relates to a low-priced high-carbon iron-based amorphous alloy using molten pig iron and a method of manufacturing the same.
(b) Description of the Related Art
An amorphous alloy refers to an alloy having an irregular (amorphous) atomic structure like liquid.
In the amorphous alloy, when metal is quenched in a molten state, in the case where the metal is cooled at high speed of no less than a critical cooling rate, since there is no time to regularly arrange atoms to be crystallized, irregular atomic arrangement in a liquid state is maintained to a solid state.
That is, in liquid cooled at higher speed than the critical cooling speed, the viscosity of the liquid is significantly increased in a supercooled liquid region of no more than an equilibrium melting point so that fluidity of atoms in the liquid is significantly reduced. Therefore, the atoms that lose fluidity at very high cooling speed are fixed in a non-equilibrium phase structure so that characteristics of a solid state are represented. An alloy having the above-described structure is referred to as an amorphous alloy.
Due to such structural characteristics of the amorphous alloy, a material having an amorphous structure represents physical, chemical, and mechanical characteristics different from those of a conventional crystalline phase. For example, the amorphous alloy represents excellent characteristics such as high strength, a low friction coefficient, high corrosion resistivity, excellent soft magnetism, and superconductivity in comparison with a common metal alloy. Therefore, the amorphous alloy as a structural and functional material has high probability with engineering applications.
Earlier studies on the amorphous alloy relate to an Au—Si alloy of eutectic composition. It is confirmed that a metal amorphous phase is formed when Au—Si liquid of such eutectic composition is quenched. After that, many researchers have conducted studies about structure and physical properties of the metal amorphous material.
The amorphous alloy is very strong elasticity and has a yield stress close to a theoretical strength, and low electric and thermal conductivity and high magnetic permeability and low coercive force. Moreover, the amorphous alloy has features of high corrosion resistance and low damping phenomenon as a medium for sound wave propagation.
It is known that the amorphous alloy has economic benefits in energy, capital, and time for the manufacturing process.
However, during the manufacturing of the amorphous alloy from liquid, in order to suppress nucleation and growth between a melting point and glass transition temperature, a sufficient cooling rate (higher than 105 to 106 K/s) is required. For these reasons, there is restriction (less than 60 nm) for thickness when manufacturing the amorphous alloy. Therefore, the amorphous alloy is manufactured by methods of enabling a rapid quenching, such as a gas atomization method, a drop tube method, a melt spinning method, and a splat quenching method.
As such, when the amorphous alloy is manufactured by the rapid quenching method, the amorphous alloy is inevitably manufactured as one- or two-dimensional specimen of easily radiating heat such as in the form of powder, ribbon, and a thin plate. However, recently applicability as high functionality and structural metal material employing features of the amorphous alloy is required. The amorphous alloy to be used as described above gradually needs excellent glass forming ability, ability of forming amorphous phase even at a lower threshold quenching rate, and possibility of being manufactured and in bulk.
Meanwhile, iron-based amorphous alloy is usually used as a magnetic material for decades and active researches for application of the same as a high functional structural material are conducted.
However, the existing iron-based amorphous alloys are made of high priced and high purified raw material with rare impurities through a carbon and impurity removing process by considering the glass forming ability or have a large amount of high priced elements, and it is hard to manufacture the iron-based amorphous alloys in bulk.
For these reasons, since the existing iron-based amorphous alloys are made accurately under the special atmosphere such as a vacuum state, an argon (Ar) gas atmosphere, etc., in the event when price of raw material increases and when to melt and cast the raw material and manufacturing costs are high, there are many problems in industrial product of the existing iron-based amorphous alloys.
Therefore, for the substantial industrial application of the useful properties of the amorphous alloys, it is required to develop an iron-based amorphous alloy which can be mass-produced by economic raw material.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.